Name: Keycard For Developers
Brand: Keycard
SKU: SKDEVV1
Price: 30.46 EUR
Availability: InStock

Keycard For Developers

€30,46

Keycard For Developers

€30,46

If you're a developer/builder and you want to build your own secure element, we provide these unfused cards where you can load yourself the applets of your choice (e.g. keycard applet) or build your own software.

The only limit to what you can do with these cards is your imagination! Join the ecosystem of projects that build around Keycard!

The card reference is a J3R200 from NXP, and is part of the JCOP4 P71 family. It's a dual interface card (NFC and contacts) with 200Kb of flash and Javacard 3.0.5.

These cards come in white only.

For security reasons, these cards don't include a keycard certificate. This won't prevent you from using the card with Shell or Status desktop/mobile, but you will get a warning message when you use it.

Follow this guide to build your own Keycard.

In stock · Delivered in 7 days

Free worldwide shipping · 50+ countries

30-day returns

Top questions

What if I lose my card or device?

Your keys live on the Keycard, protected by a PIN with limited attempts. Keep a spare Keycard or your recovery phrase as a backup, and a lost card or device never means lost funds.

How do I know it is really open source?

The Keycard applet and the Shell firmware are MIT-licensed; the hardware design is published under CERN-OHL-S v2. All of it is public on GitHub. Anyone can audit the code, build it, and verify what runs on the device.

Shipping and returns

Shipping is free and takes 7 days. Returns: yes — 30 days after delivery. As with any security product, the packaging must be unopened for a return to be accepted.

What if Keycard the company disappears?

Nothing about your wallet depends on us. Your keys follow the BIP-39 standard, so any compatible wallet can restore them. Shell signs with 15+ independent wallets — there is no Keycard app or server in the loop. And the code, schematics and card applets are open-source public goods anyone can maintain. If we vanished tomorrow, your setup would keep working.

What is an “EAL6+ secure element”?

The chip that holds your keys is a secure element — the same tamper-resistant class of chip used in bank cards and passports. EAL6+ is its Common Criteria certification, among the highest levels ever awarded to a secure element. In plain terms: your keys sit in hardware built to resist physical and software attacks — hashes go in, signatures come out, the keys never leave.

In the box

1× Keycard for developers (white)

Key features

Load any Javacard applet

Unfused JCOP4 P71 card. Load the open-source Keycard applet, build your own, or use any compatible Javacard 3.0.5 applet.

Build your own secure element

Full control over what runs on the chip. Follow the build guide to get started.

Dual interface: NFC and contact

Works over NFC (ISO 14443) and via contact reader (ISO 7816). Use it with any standard smart card reader or NFC-enabled phone.

200 KB flash storage

J3R200 reference card from NXP — 200 KB of flash for applet code and data. Plenty of room for the Keycard applet and more.

No battery, no charging

Powered entirely by the NFC field or card reader. No power management, no dead battery — always ready.

Same chip as consumer Keycard

JCOP4 P71 — EAL6+ certified secure element. The same battle-tested hardware used in the standard Keycard product.

Why should you build with Keycard?

Open platform

Unfused JCOP4 P71 — no restrictions on what you build. Your applet, your rules.

Active ecosystem

Build on top of a working ecosystem. Status and Sparrow already support the Keycard applet.

100% open source

Keycard applet is MIT-licensed. Start from a production-grade reference implementation.

EAL6+ certified hardware

The same secure element used in the consumer Keycard — the highest Common Criteria level for smart cards.

Tech specs

Form factor	ISO 7810 ID-1 — 85.6 × 54 × 0.76 mm
Chip	J3R200 from NXP (JCOP4 P71 family)
Secure element	EAL6+ certified
Interfaces	NFC (ISO 14443) + contact (ISO 7816)
Flash	200 KB
Javacard	3.0.5
Color	White only